Roller thrust bearing



Feb. 5,-1952 c. A. ABLETT 2,584,652

ROLLER THRUST BEARING Filed Nov. 14, 1949 4 Sheets-Sheet l 727 INVENTOR. Charles Antony Ablebb.

BY Mm him ATTORNEYS Feb. 5, 1952 l NVEN TOR C harlgs Anl'ozzgAblet.

Feb. 5, 1952 c. A. ABLETT ROLLER THRUST BEARING 4 Sheets-Sheet 5 Filed Nov. 14, 1949 I INVENTO Charles Anflony leap BY I ATTORNEYS Feb. 5, 1952 c. A. ABLETT 2,584,652

ROLLER THRUST BEARING Filed Nov. 14, 1943 4 Sheets-Sheet 4 F .2 i" alk t I I 1 INVENTIOIIQM'Q I .Qharles Arzi'omy Abllefifi ATTORNEYS Patented Feb. 5,1952

RUBBER, THRUST BEARI'NG Gharles Antony .Ablett, Kings Lynn, England In Great Britain J uly 5., 944

' 'Applicaflon'November 14, 1949,, Serial No. 1217,1137

.nclaims. (01. 308-434) This invention comprises improvements in roller thrust bearings and is a continuation in part of United States vliatent applications .Serial Numbers "107,911, now .abandoned, and 107912, filed July 5, 19.44, now :Patent Number 2,539,682, issued January 30., 1951.

One object of the invention is to provide an improvedzformofsplitrroller thrustsbearing which ay be adapted or adopted for use as athrust bearing block, for example as a thrust bearing block for propeller shafts such ,as are employed in marine propulsion 7 ,Another object of the invention-is to provide an improved form .of thrust bearing which can accommodate itself to deflection of the thrust surfaces or races with which the rollers engage.

Peculiar-.difiiculties.arise in the design of roller thrust bearings because the ariousparts of the bearing have to operate at differing radii .and therefore .at ldiffering peripheral speeds. The surfaces of rollers, unlike ball bearings, aiford or .arejintended to afiiordcontinuous line contact throughout the length of the roller. :Slipping of the roller surface relative to the raceway surface in whichit works is "harmful and in order to nbviate it, it is essential not only that the rollers should be disposed with their axes "radial torthe axis of the thrust'bearing, but that provision should 'be'inade fortthe peripheral speed of the rollers to '"be'grea'ter at the larger radii than at the smaller radii. It has been proposed to meet this condition by the use "of conical rollers, which are larger in diameter at the outer parts of the bearing {than they are near the axis ofthebearing, the-rollers being disposed 'so that th-eirsur'faces ifproduced would come to a point coincidentally with the *axis'. "This construction.

complies with the condition that the peripheral speed "of the rollers-should increase proportionally to the distance from the axis, butit brings in its train the disadvantage that there is a very-strong outward radial thrust -.upon the :rollers and if a roller cage is employed, the cage has :to take this thrust. "It "is however, not :desirable that a cage should be subjected to such stresses, especially. as it leads "to the necessity. of provision for taking the wear where the ends of the rollers engage the cage, which provision leads to either undue friction nor .to complication of the construction.

' If' .on .the other hand, .plainlcylindrical rollers are employed to avoid outward thrust, then as their diameter is the same throughout, 'there will be'slipping at their inner or outward ends. It has been proposed to" overcome "this by subdividing therollersin-to short radial'sections and the present invention "relates to a bearing of the typ having cylindrical rollers arrangedin groups comprising rollers of short length considered in .a direction radial to the axis of the bearing, :the construction being intended to be adapted to take heavy loads with success.

To this end, according to'the present invention, it is contemplated to employ a construction in which the support of :the :raceways :is adapted v. to accommodate itself to the effect of deflections 0 the parts .under load without leading tonneve pressureupon the bearing surfaces, wherein the cage whichlcarries-the:rolle1s isadapted to-maintain-zthem properly in place without itself producing :undue friction and wherei p ov on is made :for *a number of separate concentric raceways :to be employed if desired.

. It will be appreciated that under load conditions, there may be a tendency for the opposed flat thrust taking. and thrust imparting surfaces to move away from each other orotherwise to become displaced or distorted out of a true radial plane with the result that the gap between such surfaces or flanges may become displaced laterally or become-divergent towards theouter peripheral surface of the cage member. In this connection, it will also be appreciated that distortion of the fixed thrust surface will depend .upon .the manner in which it is supported. If it is su ported by a ,tubularstructure near theshaft, it will probably .distortso that the gap will become divergent as already stated. If, however, it is supported by a tubular structure holding the same near its outer periphery, the \distortionof thefixed abutment will probably follow the distortion of the movable abutment with the result that the said ap, instead of becoming divergent, may become displaced laterally or caused to assume a curved form. Under such circumstances, the transverse width of the gap may remain constant or may increase slightly or may decrease slightly. Accordingly, and in ordertotake care of this factor, the relatively short "rollers and/or the surfaces on the abutments with which they engage may be so arranged and formed as to enable the load to be distributed evenly and not unduly to load any onepart of the thrust bearing in the manner above described. In addition, the relatively short thrust-taking"rollers maybe formed :so thatthose farthest from "the shaft are slightly greater in diameter than those nearest to the shaft and "so that the intermediate rollers I progressively (radia'llyoutward from-the shaft) increase in diameter to such an extent as will cause or enable the rollers and the thrust surfaces to engage with each other-to secure an even distribution of the 3 load under load conditions. Furthermore, the annular portions or races of the thrust surfaces which are engaged by the relatively short thrusttaking rollers may be stepped back from one another or staggered radially outward from the axis of the shaft with similar effect, it being appreciated that in either arrangement the staggering or the diameter variations should be such as will conform with the curve of deflection produced or expected in the thrust surfaces under load conditions and will enable a proper distribution of the load to be effected.

It is to be understood that the cagemember or the annular or ring-like parts constituting the same and the races may be split or made in two or more segmental sections and suitable means provided for retaining or maintaining the individual thrust rollers in their correct positions.

Furthermore, in the case of many types of thrust bearing, including marine thrust bearings such as are referred to hereinabove, it is important to be able to ship and unship the parts without removal of the shaft. The subdividing of the cage and the races into segmental sections is of particular advantage in this connection.

Special precautions may be adopted to ensure the smooth running of the parts under heavy their axes arranged parallel with the shaft is disposed between the shaft and the inner annular or ring-like part e in order to support the weight of the cage and so that the cage cannot rub on the shaft. Each annular or ring-like part is provided with a set of radially disposed, short, thrust rollers arranged in radial groups. Along each radial line there may be one Or two or more parallel rollers, journalled in suitable radial slots or 1 openings provided'for the purpose; Around the element or annular ring.

loads notwithstanding the fact that a large number of short rollers have to run over joints in the raceways under heavy loads.

The manner in which roller bearing thrust blocks according to the present invention are constructed to meet the above conditions and the various features of such bearings according to the present invention will be apparent from the following description, which is given by way of example of certain constructions in accordance with'the invention, reference being made to the accompanying drawings, in which:

Figure 1 shows diagrammatically and in section one mode of carrying the invention into effect;

Figure 2 is a detail view of one form of split cage or series of concentric cages that may be employed to carry the short-thrust taking rollers;

Figure 3 is a diagrammatic view illustrating to an exaggerated degree one manner in which distortion may take place;

Figure 4 is another diagrammatic view illus trating also to an exaggerated degree another manner in which distortion may take place;

Figure 5 is a longitudinal section through an alternative construction;

Figure 6 is a transverse sectionupon thelline,

is indicated at a. A flange member I) is suitably secured to the shaft to form the rotary abutment of a thrust bearing. The fixed abutment is constituted by another flange member 0 and between the two abutments there is arranged a cage carrying a plurality of separate, spaced, relatively short, thrust rollers d. In the preferred form of the invention, the aforesaid cage is madeup of a plurality of separate, concentric, annular or ring-like parts each subdivided into segments as indicated at n, Figure 2, and having mounted therein one or more sets of radially-disposed, short, thrust rollers. For example, there may be provided three split or divided annular or ringlike parts such as are shown at e, f, and g. A roller bearing having a series of rollers 71. with The rotary and fixed abutments or flanges are each provided with a plurality of removable or replaceable thrust rings or races such as .are

shown at m, there being a separate ring m, for each set of thrust rollers d. Such-rings or races may be let into annular grooves formed in the fixed and rotary abutments and, if desired, the rings or races and the grooves may be mutually formed to permit slight fiexure as hereinafter more fully described.

In some instances, all of the relatively thrust-taking rollers may be of the same diameter and the thrust surfaces with which they engage may be disposed in truly radial planes so that the gap between such surfaces is of constant width. In other instances, the relatively short thrust rollers may be formed so that those farthest from the shaft are slightly greater in diameter than those nearest to the shaft and so that the intermediate rollers are of an intermediate diameter or progressively (radially outward from the shaft) increase in diameter to such an extent as will cause or enable the rollers and the thrust surfaces to engage with each other to secure an even distribution of the load under load conditions or to accommodate a distortion effect such as is illustrated to an exaggerated degree in Figure 3 in which the gap between the abutment surfaces becomes divergent or more divergent under the influence of the load. I

As already explained the manner in which the thrust surfaces will distort or .tend to distort will depend very largely upon the manner .in which the fixed abutment is supported. If it is supported in a manner such as is illustrated diagrammatically in Figure 3, the gap between the surfaces in question will tend to widen at its outer periphery or to become divergent or more divergent and, under such circumstances, it is usually preferable to employ thrust-taking rollers which at the outer part of the cage are slightly greater in diameter than those which are situated nearer to the shaft. On the other hand, if the fixed abutment is supported in a manner such as is illustrated diagrammatically in Figure 4,

way, three rollers in one group and two in the" next. In this way scoring of the race surface is obviated. It will furthermore be noted that the successive rings of the cage ;e, f and g are short 1 a'thrustcollar bzandan abutment-c. ils'be'fore.

7 together 'byscrewsss. '"Thethrustireceivmgniefiiable :to rotate relatively ito sane the rollers :on -the successive races-rare lassume the speed at which ttheyis'l'ip ileast irela tiive to-the *raceways and to-"the' c'age. cylindrical rollers on a :iiat ira'ceiit :is impossible to avoid that there :is :a:s'light :d-i'fi-erenceoisspeed between the :roller and the raceway at some mart f-.'- of the length oi "the roller in 'an:axia1 iiirection, I but the subdivision r'of rollers and arranging of a pluralityo'f them in :groups riconibined wi the subdivision :of the cage rso that-eaeh section 1 of the -cage'is capable of movement at asdifierent T speed "from the other sections, :reduces:s1ipoing l to a =point atwhieh it is immaterial ffrom 1' point .of w'iew .oi the performance 'Df ithe "shearing The :outer sections--01? zthe scage, ibteing iheld, l to gether by the .surrounding :ring 7c, screwed to t? across 'thejoint :k :(Figure' Z) Fserve toikeep all the other sections together. The gcentraiwc c'; which houses the rollers @h :is itself split and halves connected :by fishplates so that it can readily assembled over :the :s'haft .a. a 'The races m rs'h'own in-zrill :theifiguresmt ithe drawings have substantially .tplane traces to ;-;.-n-' gage the rollers 11 hutiinclin'ed :rear faces. inclined rear faces iform annular :sectionso sphere. 'IniFigure 4 of the drawings the "radius of the sphere 0f the innermost :race :is indicated at :14, fthat of the middle race :at -r ,-:and *thatqof the outer race at .1' and Lit will :be observed 1th the ,tspheres :centre ::upon .the :axis of .the :shaft as: A very small radial clearance i'iszallowedebetw n the sinner and :outeriedges :ofthe :races m and the corresponding side faces of thegrooves. in; which they .lie for reasons which *will hereinafter appear. .q l --1 Beferringvnow :to figures 5 and-f6 tot 'sthe draw ings, these fshowa roller thrust ibearingisubstan tially similar in construction :to itiiat showniin Figure 4 and comprising ::a :shaft :11 :on aviz'iiicl :is" so there "are hardened :raceways m varrange threertconcentric' grooves in pairs, zone-of pair 'bBlIlg fbEiICkdfllPlbYlthB iabntment 4c. :A the maceways .=ha-ve spherical rear suriac indicated hytheradiirrkrf, r3. a

In Figure 5 of the drawings il'iowever. hBreJS interposed between the "thrust :collario and-Ethe corresponding 1a thrust-imparting memberrt. Thiszistmadetinstwo'parts whic are sub-divided diametrically as "indicated he line :t "and the %two hahces are :screwed together by screws :s which apa'ss freely "through acne f of :.the thrust-imparting member and are .so threadedthe totherdrali. -flhethrust-aim rt- 1 ing :member isccentralised relative to :the'rs by :fitting over :a spigot :t -on the Similarly on rthe'abutment cisfarthrusts m :member u which :is likewise-split sari bar and the thrust-imparting ememberrar i of them grooved "to receive FIZGGWESS rm raceways are themselves Fsplitras indicated t m in Figure '6. The splitsz'are mot :radi are :.-inclined at an angle of about 15. radius 'so that the-a'ollers sdrpass sever the: ts gradually and zone rat a time, ;no.t.:all togetheri It is important in using split racewaysf h as themaceways m tha't theysfhould "be adequ supported and "that they sshoiild 'ibe aliowe to expand and rcontract sand. align themse order th'a t the roller "pressure upon the be as far as possible equal -at":allqnoints. connection :Ireference isamade to Figures 7 .itojflo of the drawings whichshow 'to an eularged scale .3

features id! arrangement and 311mmsmmngm the races an -the grooves of the thrust:- Limpartmg rand. .zthrust-treceiving :members, the two members :being alike in this respect. Referato .figure'i l of. :the ..-:draw;ings the rear Liaces oft-the :groore which the racewayzmember 'm is seated is zindicated at ibeing rof spherical ifaonnationsand fitting sexactly 'thenaiear 'iace hf thexrace'anember. A small clearance zw ass-provided ibetween ithe zontersedge "of the mace memberrandzthe:corresponidingziacezofthegrooye and a zsimilar olearance 3w :is provided at the inner fiace. fSDhe cefiect vth'atrthe :race :member. or racefmenibers, after it is in two -segments, are

zireettorslidemcross the plane cfithe rthrustimem- "her t :and :out to ithe extent permitted :by the clearancefia't wL ,:=w ,the:rear face beingrsph'erioal. If the ring slides to. this extent it will be sable to' align itself with the opposite raceway the other thrust'member of the :bearing :so thatbo'th of; ibear evenly on the :rollers which they engage notwithstanding that. ithe bearing "itself may lbeiminutely out of line, :the one half as comparediwith'the other. The clearance iallowed its'quite small, :nsually for :the order of one thousandthof in-ch :although it may "be greater in some :cases. The chain-line w in Figure 7 of the-drawing indicates how athe face m of :the racerring may be displaced rbynthe radial moveinent of the :ring -on its :spherical seating.

, .Beierring :toliigure {8, this .shows an additional my inawhich ftherace m :is free relatively to the otlier member 1. If the spherical :back :of the mac-eds :made to bear-hard notzall over the iace of :thesgrocve fbutiaround anarrow annulariseating near one edge of the race ;ash.indicate,d by the arrow m :the effect ;-is :that-aunderpressure trom ithE'flOHeIS :the race :ring 2m :able :to flex rand rso thesposition c oft ,its section capable 10f canting until the face comes into ;a position such as :that indicated rinan iexaggeratedsmanner :by the-chain :10 If sthe-outerrol1ers of the warriors gmups are bearing iharcier :upon "the shows I'IIOW :if :the'uzone. of, pressure is made to occur'near :the muterredge of the-back :of 113118 mane as indicated .at a :similar .flexing occurs in the opposite direction as indicated :by iithe :Zchain line 2115. iii :theggroove in which the raceway is seated is made ;a little flatter than the spherical I rear face of the :race, thezzzcneqof maximum pressure will occur in a more :central :position indicated :by the @arrow nn ,..Figure .10. vIn this way the race scan :fiex in reither direction as vindicated by the-chain lines :10 :and 3w to -equalise pressure 3011313116 rollers. ,:It will .be "understood narrow :a'a'dial dimensions :of the "rings which are shown the ':drawings, it :may begzsuflicient for thefshane-o'i the backs of the :rings to be that of a cone which is tangential to thesphere.

:heawy thrust pressures are being transmitted by the bearingvery small degrees of'lack or alignment between theshaft-a and the thrust abutment may produce substantial lateral pressures 'upon the roller cage but the roller hearing it on which the cage runs serves in such cases to prevent the development of undue frictional losses and the combinationof the measures described for ensuring alignment-and uniform loadin of the rollers together with the cage and the supporting race therefor enable very heavy thrusts to be absorbed by a roller thrust bearing according to the present invention notwithstanding the fact that the raceways, the roller cage and the thrust-imparting and receiving members are all split and so capable of ready assembly and disassembly when'required, even after the shaft is in place. This is-a point of great importance in a bearing such as a marine thrust bearing but the advantage also applies in many other engineering installations.

I claim:

1.A roller-bearing thrust-block comprising in combination a thrust-imparting member, a thrust-receiving member, said two members having opposed thrust-surfaces and being relatively rotatable, at least one raceway receiving groove in each of said opposed thrust surfaces, opposedraceways with flat race surfaces and inclined rear surfaces in each of said grooves, --a rollerbearing cage between the raceways, and cylin: drical rollers supported in said cage and disposed with their axes radial to the axis of rotation of the thrust-block, said cylindrical rollers being disposed around the raceways in groups each containing a plurality 'of co-axial rollers, the grooves in said thrust surfaces affordin radial clearance to the raceways and abutting upon the inclined backs of the raceways.

2. A roller-bearing thrust-block as claimed in claim 1 wherein the inclined rear surfaces of the raceways form sections of spheres centered upon the bearing axis.

3. A- roller-bearing thrust-block as claimed in claim 1 wherein the thrust surfaces bear on limited annular zones at the back of the raceways to permit fiexure thereof under load.'

4. A roller-bearing thrust-block as claimed in claim 1 wherein a plurality of grooves, concentric with one another, are provided in'each thrust surface, each of the grooves having aseparate raceway and all the raceways having radial clearance in the grooves and inclined backs and cylin' drical rollers arranged in radially disposed groups associated with each raceway. 1

' 5. A roller-bearing thrust-block as claimedin claim 1 wherein each of the raceways is split into at least two portions, the joints between the portions being non-radial.

6. A roller-bearing thrust-block as claimed in claim 1 wherein the thrust-imparting and thrust receiving members consists of split collars aroundthe shaft, means are provided for holding them together, the backs of the collars are machined true with the grooves in their thrust surfaces and backing members are provided, moon the rotating and one on the fixed part of the thrustblock to support the thrust-imparting and thrustreceiving members. I

'7. In a roller-bearing thrust-block having a thrust-imparting surface carried by a rotatable member and a surface ofaanabutment adapted to take thrust, a roller-bearing cage interposed between said surfaces and radially disposed relatively short cylindrical thrust rollers mounted in the cage in groups, each consisting of a plurality of such. rollers, and a plurality of rollerengaging ring-like vraces seated in annular grooves formed inat least one of the thrustimparting and thrust-taking surfaces, the rollerengaging races being formed with a clearance between the races and the grooves and a limited annular bearing on the backs of the grooves to permit slight flexing of each race as viewed in section individually and independently of other race or races relatively to the grooves and to permit the bearing surfaces of the races to align themselves with the surfaces ofthe rollers.

8.-A roller-bearing thrust-block comprisingzin combination a thrust-imparting member and thrust-taking member said members being rotatable relatively to one another, a plurality of members, a roller cage-between the thrust-imparting and thrust-taking'members, cylindrical rollers in said cage disposed so that their axes are radial, said rollers being arranged in groups with a plurality of groups disposed between eachpair of races, the groups each comprising 'a' plurality of rollers whose axial length is short relatively to the radius from the axis 'of the thrust bearing at which they operate, said races having rear surfaces to engage at least one of the thrust-imparting and thrust-taking members over a portion of the rear said surface of the races and clearance over another portion whereby the races are enabled to align themselves with the roller surfaces.

9. A roller-bearing thrust-block comprising in combination opposed flat-surfaced race members, each of said members being sub-divided into a plurality of segments, thrust-imparting and thrust-receiving members, substantially spherical seats on the said members to fit the race member segments, the race member segments being shaped to fit said seats and provided with clearance to permit-relative movement between the race member segments and the seats, a plurality of concentric series of radially disposed cylindrical rollers between the race members, a pluralityof cage members, one for each series of rollers, the cage members fitting one within another and being movable circumferentially relatively to one another, and means for maintaining the cage members concentric with the races.

10.- A roller-bearing thrust-block comprising in combination'a thrust-imparting member, a thrust-receiving member opposed thereto, a plurality of substantially spherical concentric race member seats in each of the thrustimparting and thrust-receiving members, a plurality of concentric flat-surfaced race members in said seats, each sub-divided into a plurality of segments -and dimensioned 'to afiord clearance so as to permit'slight' relative movement between said racemembers and said seats, a series of radially disposed cylindrical rollers between each pair of opposed race members, a separate cage member for each series of rollers, the'cage members being sub -divided into segments and dimensionedto fit one within another but to permit relative circumferential movement between them, means to hold the segments of the outermost cage member together and means for maintaining the cage members concentric with the races. 1

' 11. A'roller-bearingthrust-block asclaimed in claim 10 wherein each of the series of rollers between the several races consists of a series of groups of rollers, the rollers in each group being coaxial with one another.

12'. A roller-bearing thrust-block as claimed in claim 10 wherein the means for maintaining the cage members concentric with the races comprise a series of roller bearings within the innermost cage member set with their axes parallel to the axis of the thrust block.

13. A roller-bearing thrust-block as claimed in claim 12, wherein the series of rollers which are set with their axes parallel to the axis of the thrust block are spaced apart by a cage member and the cage member is split into a plurality of segments.

14. A roller-bearing thrust-block as claimed in claim 10 wherein the thrust-imparting and thrust-receiving members are sub-divided into a plurality of segments and provided with means to draw the segments of each said member to- 16 ather.

CHARLES ANTONY ABLETT.

10 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 673,220 Perkins Apr. 30, 1901 798,096 Eveland Aug. 29, 1905 FOREIGN PATENTS Number Country Date 509,004 Great Britain July 10, 1939 

